You may have to boil the question down to its base components, leading to a chicken or the egg debate.

Business development seeks to draw in potential clients and, if successful, new accounts are established and, then, depending upon the amount of business activity, the management of those accounts begins in earnest.

On the other hand, while not as often, potential clients do seek out business development firms as well. In this case, business development handlers cannot truly lay claim to an acquisition that presents itself to them.

Ultimately, you are dealing with a 50/50 scenario that is controlled by a handful of familiar and timeless parts.

In a thriving economy, where a company is offering business goods and services that are necessary / popular / of top quality, existing clients will continue to approach that company with more business. Through brilliant marketing campaigns and word of mouth from existing clients, potential new clients will knock each other over in order to get a piece of that company's action.

In a decaying economy, where a company is offering business goods and services that may be necessary / could be popular / might be of top quality, existing clients may not be able to afford to approach that company with more business, due to diminished resources for any number of reasons, both economically-related and decision-related. No matter how legitimately brilliant that company's marketing campaigns may be, no matter how admired and respected that company's officers, products, and services may be among existing clients, potential new clients may simply be suffering financially just as much as that company's existing client base.

Only the most creative business development firms, who have their collective finger on the pulse of local and international purchasing communities through tens of hundreds of in-depth focus group blitzes, in both good and bad economic times, can stand up and claim to have blurred the line between the priority of bizdev over account management or vice versa.

And the very next quarter, that creativity, that genius, and that mind-reading can dry up without explanation, and because of this unannounced, unforeseen voodoo, the proportions / ratios / silver bullets get turned on their heads.

Economies can be unpredictable, as people around the world have been experiencing lately, even when the goods and services are of top quality and being offered at incredible discounts. Your answer may be that business development and account management will always need each other in equally unpredictable doses.

Both the chicken and the egg, in this case, are on 24/7 duty, receiving no such prioritized break from the action of developing new business assets and maintaining existing business assets. And if a company’s existing clients have disappeared with no potential clients in sight, then, the debate concludes with an expired fowl and a rotten egg.